I'm a casual observer, so take this as the understanding of some dumbass on lemmy rather than anybody who's actually been in the medical field. My understanding is that the majority of "non-gendered" medical research done through history has actually been male only, given discrimination and women being hidden inside the home for a lot of history. I've also heard that young male cadavers were WAY more available in like industrial revolution england than young female cadavers (affecting both medical research and training) just given who was more likely to get a dangerous job and die young. I know modern medicine understands how to sample a population a bit better than that, but the absolute vast majority of medical research still happened in places/eras that considered women property.